[unix-history] / usr / src / sys / kern / subr_rmap.c

/*
 * Copyright (c) 1982, 1986 Regents of the University of California.
 * All rights reserved.  The Berkeley software License Agreement
 * specifies the terms and conditions for redistribution.
 *
 *	@(#)subr_rmap.c	7.6 (Berkeley) %G%
 */

#include "param.h"
#include "systm.h"
#include "map.h"
#include "dmap.h"		/* XXX */
#include "proc.h"
#include "kernel.h"

/*
 * Resource map handling routines.
 *
 * A resource map is an array of structures each
 * of which describes a segment of the address space of an available
 * resource.  The segments are described by their base address and
 * length, and sorted in address order.  Each resource map has a fixed
 * maximum number of segments allowed.  Resources are allocated
 * by taking part or all of one of the segments of the map.
 *
 * Returning of resources will require another segment if
 * the returned resources are not adjacent in the address
 * space to an existing segment.  If the return of a segment
 * would require a slot which is not available, then one of
 * the resource map segments is discarded after a warning is printed.
 * Returning of resources may also cause the map to collapse
 * by coalescing two existing segments and the returned space
 * into a single segment.  In this case the resource map is
 * made smaller by copying together to fill the resultant gap.
 *
 * N.B.: the current implementation uses a dense array and does
 * not admit the value ``0'' as a legal address, since that is used
 * as a delimiter.
 */

/*
 * Initialize map mp to have (mapsize-2) segments
 * and to be called ``name'', which we print if
 * the slots become so fragmented that we lose space.
 * The map itself is initialized with size elements free
 * starting at addr.
 */
rminit(mp, size, addr, name, mapsize)
	register struct map *mp;
	long size, addr;
	char *name;
	int mapsize;
{
	register struct mapent *ep = (struct mapent *)(mp+1);

	mp->m_name = name;
/* N.B.: WE ASSUME HERE THAT sizeof (struct map) == sizeof (struct mapent) */
	/*
	 * One of the mapsize slots is taken by the map structure,
	 * segments has size 0 and addr 0, and acts as a delimiter.
	 * We insure that we never use segments past the end of
	 * the array which is given by mp->m_limit.
	 * Instead, when excess segments occur we discard some resources.
	 */
	mp->m_limit = (struct mapent *)&mp[mapsize];
	/*
	 * Simulate a rmfree(), but with the option to
	 * call with size 0 and addr 0 when we just want
	 * to initialize without freeing.
	 */
	ep->m_size = size;
	ep->m_addr = addr;
	(++ep)->m_size = 0;
	ep->m_addr = 0;
}

/*
 * Allocate 'size' units from the given
 * map. Return the base of the allocated space.
 * In a map, the addresses are increasing and the
 * list is terminated by a 0 size.
 *
 * Algorithm is first-fit.
 *
 * This routine knows about the interleaving of the swapmap
 * and handles that.
 */
long
rmalloc(mp, size)
	register struct map *mp;
	long size;
{
	register struct mapent *ep = (struct mapent *)(mp+1);
	register int addr;
	register struct mapent *bp;
	swblk_t first, rest;

	if (size <= 0 || mp == swapmap && size > dmmax)
		panic("rmalloc");
	/*
	 * Search for a piece of the resource map which has enough
	 * free space to accomodate the request.
	 */
	for (bp = ep; bp->m_size; bp++) {
		if (bp->m_size >= size) {
			/*
			 * If allocating from swapmap,
			 * then have to respect interleaving
			 * boundaries.
			 */
			if (mp == swapmap && nswdev > 1 &&
			    (first = dmmax - bp->m_addr%dmmax) < size) {
				if (bp->m_size - first < size)
					continue;
				addr = bp->m_addr + first;
				rest = bp->m_size - first - size;
				bp->m_size = first;
				if (rest)
					rmfree(swapmap, rest, addr+size);
				return (addr);
			}
			/*
			 * Allocate from the map.
			 * If there is no space left of the piece
			 * we allocated from, move the rest of
			 * the pieces to the left.
			 */
			addr = bp->m_addr;
			bp->m_addr += size;
			if ((bp->m_size -= size) == 0) {
				do {
					bp++;
					(bp-1)->m_addr = bp->m_addr;
				} while ((bp-1)->m_size = bp->m_size);
			}
			if (mp == swapmap && addr % CLSIZE)
				panic("rmalloc swapmap");
			return (addr);
		}
	}
	return (0);
}

/*
 * Free the previously allocated space at addr
 * of size units into the specified map.
 * Sort addr into map and combine on
 * one or both ends if possible.
 */
rmfree(mp, size, addr)
	struct map *mp;
	long size, addr;
{
	struct mapent *firstbp;
	register struct mapent *bp;
	register int t;

	/*
	 * Both address and size must be
	 * positive, or the protocol has broken down.
	 */
	if (addr <= 0 || size <= 0)
		goto badrmfree;
	/*
	 * Locate the piece of the map which starts after the
	 * returned space (or the end of the map).
	 */
	firstbp = bp = (struct mapent *)(mp + 1);
	for (; bp->m_addr <= addr && bp->m_size != 0; bp++)
		continue;
	/*
	 * If the piece on the left abuts us,
	 * then we should combine with it.
	 */
	if (bp > firstbp && (bp-1)->m_addr+(bp-1)->m_size >= addr) {
		/*
		 * Check no overlap (internal error).
		 */
		if ((bp-1)->m_addr+(bp-1)->m_size > addr)
			goto badrmfree;
		/*
		 * Add into piece on the left by increasing its size.
		 */
		(bp-1)->m_size += size;
		/*
		 * If the combined piece abuts the piece on
		 * the right now, compress it in also,
		 * by shifting the remaining pieces of the map over.
		 */
		if (bp->m_addr && addr+size >= bp->m_addr) {
			if (addr+size > bp->m_addr)
				goto badrmfree;
			(bp-1)->m_size += bp->m_size;
			while (bp->m_size) {
				bp++;
				(bp-1)->m_addr = bp->m_addr;
				(bp-1)->m_size = bp->m_size;
			}
		}
		goto done;
	}
	/*
	 * Don't abut on the left, check for abutting on
	 * the right.
	 */
	if (addr+size >= bp->m_addr && bp->m_size) {
		if (addr+size > bp->m_addr)
			goto badrmfree;
		bp->m_addr -= size;
		bp->m_size += size;
		goto done;
	}
	/*
	 * Don't abut at all.  Make a new entry
	 * and check for map overflow.
	 */
	do {
		t = bp->m_addr;
		bp->m_addr = addr;
		addr = t;
		t = bp->m_size;
		bp->m_size = size;
		bp++;
	} while (size = t);
	/*
	 * Segment at bp is to be the delimiter;
	 * If there is not room for it 
	 * then the table is too full
	 * and we must discard something.
	 */
	if (bp+1 > mp->m_limit) {
		/*
		 * Back bp up to last available segment.
		 * which contains a segment already and must
		 * be made into the delimiter.
		 * Discard second to last entry,
		 * since it is presumably smaller than the last
		 * and move the last entry back one.
		 */
		bp--;
		printf("%s: rmap ovflo, lost [%d,%d)\n", mp->m_name,
		    (bp-1)->m_addr, (bp-1)->m_addr+(bp-1)->m_size);
		bp[-1] = bp[0];
		bp[0].m_size = bp[0].m_addr = 0;
	}
done:
	/*
	 * THIS IS RIDICULOUS... IT DOESN'T BELONG HERE!
	 */
	if ((mp == kernelmap) && kmapwnt) {
		kmapwnt = 0;
		wakeup((caddr_t)kernelmap);
	}
	return;
badrmfree:
	panic("bad rmfree");
}

/*
 * Allocate 'size' units from the given map, starting at address 'addr'.
 * Return 'addr' if successful, 0 if not.
 * This may cause the creation or destruction of a resource map segment.
 *
 * This routine will return failure status if there is not enough room
 * for a required additional map segment.
 *
 * An attempt to use this on 'swapmap' will result in
 * a failure return.  This is due mainly to laziness and could be fixed
 * to do the right thing, although it probably will never be used.
 */
rmget(mp, size, addr)
	register struct map *mp;
{
	register struct mapent *ep = (struct mapent *)(mp+1);
	register struct mapent *bp, *bp2;

	if (size <= 0)
		panic("rmget");
	if (mp == swapmap)
		return (0);
	/*
	 * Look for a map segment containing the requested address.
	 * If none found, return failure.
	 */
	for (bp = ep; bp->m_size; bp++)
		if (bp->m_addr <= addr && bp->m_addr + bp->m_size > addr)
			break;
	if (bp->m_size == 0)
		return (0);

	/*
	 * If segment is too small, return failure.
	 * If big enough, allocate the block, compressing or expanding
	 * the map as necessary.
	 */
	if (bp->m_addr + bp->m_size < addr + size)
		return (0);
	if (bp->m_addr == addr)
		if (bp->m_addr + bp->m_size == addr + size) {
			/*
			 * Allocate entire segment and compress map
			 */
			bp2 = bp;
			while (bp2->m_size) {
				bp2++;
				(bp2-1)->m_addr = bp2->m_addr;
				(bp2-1)->m_size = bp2->m_size;
			}
		} else {
			/*
			 * Allocate first part of segment
			 */
			bp->m_addr += size;
			bp->m_size -= size;
		}
	else
		if (bp->m_addr + bp->m_size == addr + size) {
			/*
			 * Allocate last part of segment
			 */
			bp->m_size -= size;
		} else {
			/*
			 * Allocate from middle of segment, but only
			 * if table can be expanded.
			 */
			for (bp2=bp; bp2->m_size; bp2++)
				;
			if (bp2 + 1 >= mp->m_limit)
				return (0);
			while (bp2 > bp) {
				(bp2+1)->m_addr = bp2->m_addr;
				(bp2+1)->m_size = bp2->m_size;
				bp2--;
			}
			(bp+1)->m_addr = addr + size;
			(bp+1)->m_size =
			    bp->m_addr + bp->m_size - (addr + size);
			bp->m_size = addr - bp->m_addr;
		}
	return (addr);
}
Commit	Line	Data
da7c5cc6	1	/*
0880b18e	2	* Copyright (c) 1982, 1986 Regents of the University of California.
da7c5cc6 KM	3	* All rights reserved. The Berkeley software License Agreement
	4	* specifies the terms and conditions for redistribution.
	5	*
8429d022	6	* @(#)subr_rmap.c 7.6 (Berkeley) %G%
da7c5cc6	7	*/
2694e78a	8
94368568 JB	9	#include "param.h"
	10	#include "systm.h"
	11	#include "map.h"
8429d022	12	#include "dmap.h" /* XXX */
94368568	13	#include "proc.h"
94368568	14	#include "kernel.h"
2694e78a	15
b725a0ca BJ	16	/*
	17	* Resource map handling routines.
	18	*
	19	* A resource map is an array of structures each
	20	* of which describes a segment of the address space of an available
	21	* resource. The segments are described by their base address and
	22	* length, and sorted in address order. Each resource map has a fixed
	23	* maximum number of segments allowed. Resources are allocated
	24	* by taking part or all of one of the segments of the map.
	25	*
	26	* Returning of resources will require another segment if
	27	* the returned resources are not adjacent in the address
	28	* space to an existing segment. If the return of a segment
	29	* would require a slot which is not available, then one of
	30	* the resource map segments is discarded after a warning is printed.
	31	* Returning of resources may also cause the map to collapse
	32	* by coalescing two existing segments and the returned space
	33	* into a single segment. In this case the resource map is
	34	* made smaller by copying together to fill the resultant gap.
	35	*
	36	* N.B.: the current implementation uses a dense array and does
	37	* not admit the value ``0'' as a legal address, since that is used
	38	* as a delimiter.
	39	*/
	40
	41	/*
	42	* Initialize map mp to have (mapsize-2) segments
	43	* and to be called ``name'', which we print if
	44	* the slots become so fragmented that we lose space.
	45	* The map itself is initialized with size elements free
	46	* starting at addr.
	47	*/
	48	rminit(mp, size, addr, name, mapsize)
	49	register struct map *mp;
a29f7995	50	long size, addr;
b725a0ca BJ	51	char *name;
	52	int mapsize;
	53	{
	54	register struct mapent ep = (struct mapent )(mp+1);
	55
	56	mp->m_name = name;
	57	/* N.B.: WE ASSUME HERE THAT sizeof (struct map) == sizeof (struct mapent) */
	58	/*
	59	* One of the mapsize slots is taken by the map structure,
	60	* segments has size 0 and addr 0, and acts as a delimiter.
	61	* We insure that we never use segments past the end of
	62	* the array which is given by mp->m_limit.
	63	* Instead, when excess segments occur we discard some resources.
	64	*/
	65	mp->m_limit = (struct mapent *)&mp[mapsize];
	66	/*
	67	* Simulate a rmfree(), but with the option to
	68	* call with size 0 and addr 0 when we just want
	69	* to initialize without freeing.
	70	*/
	71	ep->m_size = size;
	72	ep->m_addr = addr;
92d92331 MK	73	(++ep)->m_size = 0;
92d92331 MK	74	ep->m_addr = 0;
b725a0ca BJ	75	}
b725a0ca BJ	76
2694e78a BJ	77	/*
2694e78a BJ	78	* Allocate 'size' units from the given
b725a0ca	79	* map. Return the base of the allocated space.
2694e78a BJ	80	* In a map, the addresses are increasing and the
2694e78a BJ	81	* list is terminated by a 0 size.
b725a0ca	82	*
2694e78a	83	* Algorithm is first-fit.
b725a0ca BJ	84	*
	85	* This routine knows about the interleaving of the swapmap
	86	* and handles that.
2694e78a	87	*/
39d536e6	88	long
b725a0ca BJ	89	rmalloc(mp, size)
b725a0ca BJ	90	register struct map *mp;
39d536e6	91	long size;
2694e78a	92	{
b725a0ca BJ	93	register struct mapent ep = (struct mapent )(mp+1);
	94	register int addr;
	95	register struct mapent *bp;
41888f16	96	swblk_t first, rest;
2694e78a	97
d668d9ba	98	if (size <= 0 \|\| mp == swapmap && size > dmmax)
b725a0ca BJ	99	panic("rmalloc");
	100	/*
	101	* Search for a piece of the resource map which has enough
	102	* free space to accomodate the request.
	103	*/
	104	for (bp = ep; bp->m_size; bp++) {
2694e78a	105	if (bp->m_size >= size) {
b725a0ca BJ	106	/*
	107	* If allocating from swapmap,
	108	* then have to respect interleaving
	109	* boundaries.
	110	*/
d668d9ba	111	if (mp == swapmap && nswdev > 1 &&
c1954620	112	(first = dmmax - bp->m_addr%dmmax) < size) {
41888f16 BJ	113	if (bp->m_size - first < size)
41888f16 BJ	114	continue;
b725a0ca	115	addr = bp->m_addr + first;
41888f16 BJ	116	rest = bp->m_size - first - size;
	117	bp->m_size = first;
	118	if (rest)
b725a0ca BJ	119	rmfree(swapmap, rest, addr+size);
b725a0ca BJ	120	return (addr);
41888f16	121	}
b725a0ca BJ	122	/*
	123	* Allocate from the map.
	124	* If there is no space left of the piece
	125	* we allocated from, move the rest of
	126	* the pieces to the left.
	127	*/
	128	addr = bp->m_addr;
2694e78a BJ	129	bp->m_addr += size;
	130	if ((bp->m_size -= size) == 0) {
	131	do {
	132	bp++;
	133	(bp-1)->m_addr = bp->m_addr;
	134	} while ((bp-1)->m_size = bp->m_size);
	135	}
b725a0ca BJ	136	if (mp == swapmap && addr % CLSIZE)
	137	panic("rmalloc swapmap");
	138	return (addr);
2694e78a BJ	139	}
2694e78a BJ	140	}
b725a0ca	141	return (0);
2694e78a BJ	142	}
	143
	144	/*
b725a0ca	145	* Free the previously allocated space at addr
2694e78a	146	* of size units into the specified map.
b725a0ca	147	* Sort addr into map and combine on
2694e78a BJ	148	* one or both ends if possible.
2694e78a BJ	149	*/
b725a0ca BJ	150	rmfree(mp, size, addr)
b725a0ca BJ	151	struct map *mp;
39d536e6	152	long size, addr;
2694e78a	153	{
b725a0ca BJ	154	struct mapent *firstbp;
b725a0ca BJ	155	register struct mapent *bp;
2694e78a BJ	156	register int t;
2694e78a BJ	157
b725a0ca BJ	158	/*
	159	* Both address and size must be
	160	* positive, or the protocol has broken down.
	161	*/
	162	if (addr <= 0 \|\| size <= 0)
	163	goto badrmfree;
	164	/*
	165	* Locate the piece of the map which starts after the
	166	* returned space (or the end of the map).
	167	*/
	168	firstbp = bp = (struct mapent *)(mp + 1);
	169	for (; bp->m_addr <= addr && bp->m_size != 0; bp++)
2694e78a	170	continue;
b725a0ca BJ	171	/*
	172	* If the piece on the left abuts us,
	173	* then we should combine with it.
	174	*/
	175	if (bp > firstbp && (bp-1)->m_addr+(bp-1)->m_size >= addr) {
	176	/*
	177	* Check no overlap (internal error).
	178	*/
	179	if ((bp-1)->m_addr+(bp-1)->m_size > addr)
	180	goto badrmfree;
	181	/*
	182	* Add into piece on the left by increasing its size.
	183	*/
2694e78a	184	(bp-1)->m_size += size;
b725a0ca BJ	185	/*
	186	* If the combined piece abuts the piece on
	187	* the right now, compress it in also,
	188	* by shifting the remaining pieces of the map over.
	189	*/
	190	if (bp->m_addr && addr+size >= bp->m_addr) {
	191	if (addr+size > bp->m_addr)
	192	goto badrmfree;
2694e78a BJ	193	(bp-1)->m_size += bp->m_size;
	194	while (bp->m_size) {
	195	bp++;
	196	(bp-1)->m_addr = bp->m_addr;
	197	(bp-1)->m_size = bp->m_size;
	198	}
	199	}
b725a0ca BJ	200	goto done;
	201	}
	202	/*
	203	* Don't abut on the left, check for abutting on
	204	* the right.
	205	*/
	206	if (addr+size >= bp->m_addr && bp->m_size) {
	207	if (addr+size > bp->m_addr)
	208	goto badrmfree;
	209	bp->m_addr -= size;
	210	bp->m_size += size;
	211	goto done;
	212	}
	213	/*
	214	* Don't abut at all. Make a new entry
	215	* and check for map overflow.
	216	*/
	217	do {
	218	t = bp->m_addr;
	219	bp->m_addr = addr;
	220	addr = t;
	221	t = bp->m_size;
	222	bp->m_size = size;
	223	bp++;
	224	} while (size = t);
	225	/*
	226	* Segment at bp is to be the delimiter;
	227	* If there is not room for it
	228	* then the table is too full
	229	* and we must discard something.
	230	*/
	231	if (bp+1 > mp->m_limit) {
	232	/*
	233	* Back bp up to last available segment.
	234	* which contains a segment already and must
	235	* be made into the delimiter.
	236	* Discard second to last entry,
	237	* since it is presumably smaller than the last
	238	* and move the last entry back one.
	239	*/
	240	bp--;
f4c13170	241	printf("%s: rmap ovflo, lost [%d,%d)\n", mp->m_name,
b725a0ca BJ	242	(bp-1)->m_addr, (bp-1)->m_addr+(bp-1)->m_size);
	243	bp[-1] = bp[0];
	244	bp[0].m_size = bp[0].m_addr = 0;
2694e78a	245	}
b725a0ca BJ	246	done:
	247	/*
	248	* THIS IS RIDICULOUS... IT DOESN'T BELONG HERE!
	249	*/
2694e78a BJ	250	if ((mp == kernelmap) && kmapwnt) {
	251	kmapwnt = 0;
	252	wakeup((caddr_t)kernelmap);
	253	}
b725a0ca BJ	254	return;
	255	badrmfree:
	256	panic("bad rmfree");
2694e78a	257	}
1c1f6ecf BF	258
	259	/*
	260	* Allocate 'size' units from the given map, starting at address 'addr'.
	261	* Return 'addr' if successful, 0 if not.
	262	* This may cause the creation or destruction of a resource map segment.
	263	*
	264	* This routine will return failure status if there is not enough room
	265	* for a required additional map segment.
	266	*
	267	* An attempt to use this on 'swapmap' will result in
	268	* a failure return. This is due mainly to laziness and could be fixed
	269	* to do the right thing, although it probably will never be used.
	270	*/
	271	rmget(mp, size, addr)
	272	register struct map *mp;
	273	{
	274	register struct mapent ep = (struct mapent )(mp+1);
	275	register struct mapent bp, bp2;
	276
	277	if (size <= 0)
	278	panic("rmget");
	279	if (mp == swapmap)
	280	return (0);
	281	/*
	282	* Look for a map segment containing the requested address.
	283	* If none found, return failure.
	284	*/
	285	for (bp = ep; bp->m_size; bp++)
	286	if (bp->m_addr <= addr && bp->m_addr + bp->m_size > addr)
	287	break;
	288	if (bp->m_size == 0)
	289	return (0);
	290
	291	/*
	292	* If segment is too small, return failure.
	293	* If big enough, allocate the block, compressing or expanding
	294	* the map as necessary.
	295	*/
	296	if (bp->m_addr + bp->m_size < addr + size)
	297	return (0);
	298	if (bp->m_addr == addr)
	299	if (bp->m_addr + bp->m_size == addr + size) {
	300	/*
	301	* Allocate entire segment and compress map
	302	*/
	303	bp2 = bp;
	304	while (bp2->m_size) {
	305	bp2++;
	306	(bp2-1)->m_addr = bp2->m_addr;
	307	(bp2-1)->m_size = bp2->m_size;
	308	}
	309	} else {
	310	/*
	311	* Allocate first part of segment
	312	*/
	313	bp->m_addr += size;
	314	bp->m_size -= size;
	315	}
	316	else
	317	if (bp->m_addr + bp->m_size == addr + size) {
	318	/*
	319	* Allocate last part of segment
	320	*/
	321	bp->m_size -= size;
322	} else {
323	/*
324	* Allocate from middle of segment, but only
325	* if table can be expanded.
326	*/
327	for (bp2=bp; bp2->m_size; bp2++)
328	;
93cf8c06	329	if (bp2 + 1 >= mp->m_limit)
1c1f6ecf BF	330	return (0);
	331	while (bp2 > bp) {
	332	(bp2+1)->m_addr = bp2->m_addr;
	333	(bp2+1)->m_size = bp2->m_size;
	334	bp2--;
	335	}
	336	(bp+1)->m_addr = addr + size;
	337	(bp+1)->m_size =
	338	bp->m_addr + bp->m_size - (addr + size);
	339	bp->m_size = addr - bp->m_addr;
	340	}
	341	return (addr);
	342	}